The present invention relates to a device and process for determining the properties of reflective bodies and especially of heterogeneous reflective bodies. The visual characteristics of a body, respectively of a surface are, in a number of products, an important feature for the product's overall appearance. In order to achieve a high reproducibility during manufacturing or in the repairing of objects, measurements are thus made on prototypes or products for purposes of quality control in which one or several parameters are determined.
Particularly with finished surfaces, but not limited solely thereto, their visual properties may change depending upon viewing angle or angle of illumination. Such surfaces are called goniochromatic. Examples of such surfaces are those with effect, metallic or pearl lustre finishes, coated surfaces with interference color surfaces, or other synthetic surfaces or bodies having inlaid transparent or reflective particles or the like.
Heterogeneous reflective bodies include, for example, finished surfaces with inlaid metallic particles. Such surfaces are often smooth and unstructured.
Surfaces may exhibit, for example, so-called FLOP effects so that a change in color or gloss dependant upon the viewing angle may be observed.
Such effects may be induced, for example, by inlaid aluminum particles embedded in the surface or in the body itself and which then act as reflective material inclusions.
Measuring devices which illuminate a measurement surface at an angle and which measure the light reflected at, for example, two fixed angle ranges in order to determine the color of a surface to be appraised under these two scanning angles are known from the prior art.
Furthermore, goniometric measuring devices are also known in the prior art with which, for example, a surface is illuminated at a fixed angle and a movable photosensor is trammed across the entire angle range in order to obtain the surface color as a function of the scanning angle.
It is the task of the present invention to provide an improved device and an improved process of the type as indicated above for the determining of at least one property of a heterogeneous reflective body.
A further aspect of the task of the present invention is to provide a device which can determine at least one statistical property of a heterogeneous reflective body.
This task is solved in accordance with the present inventive device. The inventive process is also disclosed.
Preferred embodiments of the invention will also be described.